Production of light olefins

Abstract

This invention is directed to a process for producing olefin product from an oxygenate feed that includes dimethyl ether (DME). The process uses an olefin forming catalyst that contains a porous crystalline material, preferably a porous crystalline aluminosilicate molecular sieve material. The process produces high quantities of light olefin (i.e., ethylene, propylene, and mixtures thereof).

What is claimed is: 
     
       1. A multi-staged process of alternating contacting an olefin forming catalyst with dimethyl ether (DME) and methanol for producing an olefin product, comprising:
 contacting in a first stage a first oxygenate feed consisting of less than 50 wt % DME, based on the total weight of the feed, as well as diluent, with the catalyst comprising a porous crystalline aluminosilicate; 
 contacting in a second stage a second oxygenate feed consisting of at least 50 wt % methanol (MeOH), based on total weight of the feed, as well as diluent, with an olefin forming catalyst comprising a porous crystalline aluminosilicate; 
 and recovering an olefin product; 
 wherein the porous crystalline aluminosilicate is a mixture or intergrowth containing a chabazite and AEI framework with a molar relationship of:
   X 2 O 3 :( n )YO 2 , 
 
 wherein X is a trivalent element, Y is a tetravalent element and n is greater than 20; and 
 forming the olefin product; and 
 wherein the change from the first to second oxygenate feed is immediate. 
 
     
     
       2. The process of  claim 1 , wherein the oxygenate feed is contacted with the olefin forming catalyst at an average reactor temperature in the range of from 200° C. to 1000° C. 
     
     
       3. The process of  claim 1 , wherein n is at least 30. 
     
     
       4. The process of  claim 1 , wherein n is at least 50. 
     
     
       5. The process of  claim 1 , wherein n is at least 100. 
     
     
       6. The process of  claim 1 , wherein X is selected from aluminum, boron, iron, indium, and/or gallium and Y is selected from silicon, tin, titanium and/or germanium. 
     
     
       7. The process of  claim 1 , wherein X is aluminum and Y includes silicon. 
     
     
       8. The process of  claim 1 , wherein the contacting of the oxygenate with the olefin forming catalyst forms an olefin product having an ethylene to propylene weight ratio increased by at least 5% relative to that when using 100 wt % methanol as feed at the same conversion conditions. 
     
     
       9. The process of  claim 1 , wherein the olefin forming catalyst is contacted with the oxygenate feed until the olefin forming catalyst is deposited with a coke deposit of 20% or more, based on percent of maximum coke content, and the coke deposited catalyst is then contacted with a second oxygenate feed containing at least 50 wt % methanol, based on total weight of the second oxygenate feed. 
     
     
       10. The process of  claim 1 , wherein olefin from the olefin product is contacted with a polyolefin forming catalyst to form a polyolefin. 
     
     
       11. The process of  claim 1 , wherein at least one of the following is satisfied:
 (i) the olefin forming catalyst comprises at least in part a CHA type framework; 
 (ii) the olefin product has an ethylene to propylene weight ratio of at least 1.0, when subject to an average reactor temperature from 200° C. to less than 520° C.; and 
 (iii) the olefin product has an ethylene to propylene weight ratio of at least 1.35, when subject to an average reactor temperature from 520° C. to 1000° C. 
 
     
     
       12. A multi-staged process alternating contacting a catalyst with dimethyl ether (DME) and methanol for producing an olefin product, comprising:
 providing an olefin forming aluminosilicate catalyst comprising a porous crystalline aluminosilicate having a mixture or intergrowth containing a chabazite and AEI framework with a molar relationship of:
   X 2 O 3 :( n )YO 2 :( m )R: z H 2 O, 
 
 wherein X is a trivalent element, Y is a tetravalent element, n is greater than 20, R is a directing agent, m ranges from 15 to 350, and z ranges from 0 to 10; 
 removing the directing agent to form an active olefin forming catalyst; and 
 contacting in a first stage a first oxygenate feed consisting of less than 50 wt % dimethyl ether (DME) as well as diluent, based on the total weight of the feed, with the catalyst; 
 contacting the active olefin forming catalyst in a second stage a second oxygenate feed consisting of at least 50 wt % methanol (MeOH) as well as diluent, based on total weight of the feed, to form the olefin product; 
 wherein the change from the first to second oxygenate feed is immediate. 
 
     
     
       13. The process of  claim 12 , wherein R comprises at least one cyclic amine or ammonium compound. 
     
     
       14. The process of  claim 12 , wherein R comprises at least one multi-cyclic amine or ammonium compound. 
     
     
       15. The process of  claim 12 , wherein m ranges from about 30 to about 50. 
     
     
       16. The process of  claim 12 , wherein n is at least 30. 
     
     
       17. The process of  claim 16 , wherein n is at least 50. 
     
     
       18. The process of  claim 17 , wherein n is at least 100. 
     
     
       19. The process of  claim 12 , wherein X is selected from aluminum, boron, iron, indium, and/or gallium and Y is selected from silicon, tin, titanium and/or germanium. 
     
     
       20. The process of  claim 12 , wherein X is aluminum and Y includes silicon. 
     
     
       21. The process of  claim 12 , wherein oxygenate feed contains at least 25 wt % dimethyl ether, based on total weight of the feed. 
     
     
       22. The process of  claim 12 , wherein the oxygenate feed is contacted with the olefin forming catalyst at an average reactor temperature in the range of from 200° C. to 1000° C. 
     
     
       23. The process of  claim 12 , wherein the contacting of the oxygenate with the olefin forming catalyst forms an olefin product having an ethylene to propylene weight ratio increased by at least 5% relative to that when using 100 wt % methanol as feed at the same conversion conditions. 
     
     
       24. The process of  claim 12 , wherein the olefin forming catalyst is contacted with the oxygenate feed until the olefin forming catalyst is deposited with a coke deposit of 20% or more, based on percent of maximum coke content, and the coke deposited catalyst is then contacted with a second oxygenate feed containing at least 50 wt % methanol, based on total weight of the second oxygenate feed. 
     
     
       25. The process of  claim 12 , wherein olefin from the olefin product is contacted with a polyolefin forming catalyst to form a polyolefin. 
     
     
       26. The process of  claim 12 , wherein at least one of the following is satisfied:
 (i) the olefin forming catalyst comprises at least in part a CHA type framework; 
 (ii) the olefin product has an ethylene to propylene weight ratio of at least 1.0, when subject to an average reactor temperature from 200° C. to less than 520° C.; and 
 (iii) the olefin product has an ethylene to propylene weight ratio of at least 1.35, when subject to an average reactor temperature from 520° C. to 1000° C.